Free-Space Lens Design Method

1. A method of making a curved lens spanning an area having an inside reflective 3D surface, comprising: providing a computing device including a processor running an optical design algorithm; said optical design algorithm implementing: defining a plurality of oxels across said area, each of said plurality of oxels having a plurality of sub-elements including a center sub-element (CS) and a plurality of neighboring sub-elements; calculating an optically corrected reference 3D surface at each of said plurality of oxels across said area having spherical and cylindrical corrections relative to a spherical contour which together span a predetermined field of view (FOV) with respect to a single (common) predetermined reference point based on a defined optical prescription for said inside reflective surface, moving a position of at least a first of said plurality of sub-elements for each of said plurality of oxels to approach respective final 3D positions on said optically corrected reference 3D surface, wherein said moving is constrained to be along an individual fixed line connecting each of said first sub-elements to said single predetermined reference point, and forming said inside reflective 3D surface utilizing a process comprising 3D printing, machining, molding or laser ablation from a material based on said positions of said sub-elements for each of said plurality of oxels, wherein said area of said inside reflective 3D surface has a changing surface radius of curvature.

2. The method of claim 1 , wherein said at least a first of said plurality of sub-elements comprises said plurality of neighboring sub-elements, so that said moving comprises moving respective positions of said plurality of neighboring sub-elements for each said plurality of oxels, further comprising before said moving: comparing current 3D positions of said plurality of neighboring sub-elements for each of said plurality of oxels to said optically corrected reference 3D surface; detecting 3D errors in said current 3D positions of said plurality of neighboring sub-elements relative to said optically corrected reference 3D surface along said individual fixed lines, and averaging said 3D error for each of said plurality of neighboring sub-elements, wherein said moving comprises a plurality of sub-moves for each of said plurality of neighboring sub-elements before approaching said optically corrected reference 3D surface, and said comparing, detecting and averaging is iteratively repeated after each of said plurality of sub-moves.

3. The method of claim 1 , wherein said defined optical prescription for said inside reflective surface comprises a particular optical prescription for each of said plurality of oxels so that said area of said inside reflective surface focuses an incident beam of light of a first image so that objects in said first image appear at a fixed virtual distance despite an angular spread of said light from a pixel source to each of said plurality of oxels.

4. The method of claim 1 , wherein after said moving each of said plurality of oxels provide a different combined optical power for spheroidal power correction and cylindrical power correction.

5. The method of claim 1 , wherein said single predetermined reference point is associated with a proscribed eye location.

6. The method of claim 1 , wherein said curved lens comprises a beam splitter and said material is partially transmissive to visible light.

7. The method of claim 1 , wherein said curved lens comprises a meniscus lens.